The Teeth- pages 473-475
Function of Teeth
 Digestive: via mastication (chewing)
 Teeth aid in mechanical digestion, in conjunction with
the tongue, by breaking food into smaller pieces
 This speeds up the chemical digestive process
Arrangement and Dentition
 Location: located in sockets called alveoli
 Mandible (lower)
 Maxilla (upper)
 Deciduous Teeth (milk teeth) : primary dentition
 Appear at 6 months
 Completed by 2 years (20 teeth)
 Fall out between 6-12 years

Permanent teeth get larger causing resorption
 Resorption of roots causes teeth to loosen
Permanent and Wisdom Teeth
 Permanent:
 Established at the end of adolescence
 Full set is 32 teeth
 Wisdom (third molars):
 Emerge between 17-25 years old
 Can be absent in some individuals
 Impacted wisdom teeth:

Wisdom teeth remain embedded and push on the roots of
other teeth
 Causes pressure and pain
Classification of Teeth:
 Classification by shape
and function:
 Incisors: to snip off
food
 Canines: to tear and
pierce
 Premolars
(bicuspids): 2-cusp
grinders
 Molars: 4-5 cusps; best
grinders
Deciduous vs. Permanent Teeth
Numbers of Teeth
(expressed as only half of the mouth)
Deciduous Teeth = 20 total
• On each layer:
Permanent Teeth = 32 total
• 2I, 1C, 2M =
• 2I, 1C, 2M =
• 2I, 1C, 2P, 3M = 8
• 2I, 1C, 2P, 3M = 8
• 10 x 2 = 20
5
5
• On each layer:
• 16 x 2 = 32
Tooth Structure:
 Teeth have 2 main regions:
 Crown: (exposed part):



Covered by enamel (hardest substance in the body)
Dentin underlies enamel – comprises bulk of tooth
 Similar to bone in mineral and collagen components
Pulp: makes up the middle part of the tooth
 Loose connective tissue
 Root:


An extension of the pulp cavity, which contains the blood and
nerve supply
Surrounded by cementum – a calcified connective tissue
Nerve/Arterial Supply & Disorders
 The trigeminal nerve is the main nerve supplying teeth
 The arterial supply comes from branches of the carotid
 Disorders:
 Gingivitis: inflammation of the gingiva

Caused by increased deposits of plaque which increase bacterial
populations
 Periodontitis: when gingivitis causes infection of the bone
and the teeth fall out
Lesson Learned:
 Brush your teeth after you
eat
 Don’t let sugar sit on your
teeth
 Floss daily
 Go to the dentist at least
2x/year to get cleanings
 ONLY TAKE CARE OF
THE TEETH YOU WANT
TO KEEP!